Split Second
by LoveNeverDies78
Summary: AU. On the day Sirius runs away from Grimmauld Place, Regulus makes a choice that alters the course of the Black family forever.
**A/N:** I'd like to credit **MissSadieKane** for the prompt for this one. This one flowed pretty easily for me, so thanks!

 **Weekly Character Appreciation Challenge:** Regulus week

 **If You Dare Challenge:** 516\. Choice

 **The Restricted Collection:** 20\. No references to a Hogwarts house

* * *

Slamming doors and raised voices were nothing to Regulus anymore. If his mother and his brother weren't arguing about something at least once a day, it meant that one or the other of them wasn't home. Regulus just shook his head and concentrated on his Transfiguration essay, due at the beginning of the school year, and blocked out the sounds of the heated argument.

A new sound made Regulus sit up straight in his chair, straining to listen closer. Breaking glass couldn't be a good sign. He heard the door to his father's study open and then slam shut, and knew that things were about to get much worse for Sirius. Father never got involved in these arguments.

Standing up so quickly he sent his chair toppling over, Regulus rushed out of his bedroom and down the stairs. He spotted Mother and Father, their backs to him, facing the main entrance, and Sirius leaning with his back against the door, his hand on the handle, looking ready to bolt at the first opportunity. Regulus silently approached this scene, noting the broken mirror in the hall and wondering how that had happened.

"You will not speak of such nonsense in my house!" Mother shrieked. "You will not sully the noble blood of the Black family by taking up with some impure hussy!"

"I'll do whatever I please, Walburga!" Sirius shot back. "Marlene is a thousand times the woman you are!"

"Show your mother proper respect!" Father bellowed. "You've known all your life that you're intended as a husband for Bellatrix. We must keep our blood pure or our great family will be ruined!"

Sirius made a derisive noise. "You actually think I'm going to let you marry me off to my own cousin? Just because the two of you did it doesn't make it right. Besides, if you-"

Regulus jumped as the slap echoed in the small space. Mother had often handled them roughly as children when they got into trouble, but she had never actually hit them. Even Sirius looked stunned as a red mark bloomed on the side of his face, taking the shape of a hand.

"I WILL NOT BE DISRESPECTED!" Mother shrilled. "YOU WILL DO AS I SAY OR THERE WILL BE SEVERE CONSEQUENCES!"

Regulus could see that Sirius was positively seething at this point. Despite their strained relationship, Regulus felt sorry for Sirius. He didn't belong in this family. He was too vastly different from them all, the odd one out. He'd only ever wanted to see his brother as happy at home as he was at Hogwarts among his friends.

Sirius flung open the door behind him, the sound and scent of rain pouring in as he did so. "I don't have to take this anymore," Sirius said quietly, barely audible above the sound of the rain.

"Walk out that door and you'll never be allowed back in!" Father warned. "I'll make sure you're disinherited. You'll be penniless and homeless, without a family. Is that what you want?"

This was too much. Regulus felt like he'd been walking blindly through life up until his father uttered those words. Now he saw his parents for what they truly were: Proud, unfeeling, and cruel. Far too willingly to turn their own son out of the house because he didn't believe as they did.

Storming forward before he could change his mind, Regulus pushed past his parents and stood by his brother. "He won't be entirely without a family," he stated matter-of-factly. "If you disown him, then you disown me."

 _What am I doing?!_ Regulus temporarily wavered in his hasty decision to throw his entire life away, but then saw that red hand mark on his brother's face and knew exactly what he was doing. _The right thing, that's what._

"Reg, what are you - why -" Sirius sputtered. His expression was one of complete shock.

"Regulus Arcturus Black!" Mother spat. "I expect stupid, rash decisions from your brother, but not you! What do you think you're doing?"

"Something I should've done a long time ago," Regulus replied, keeping his voice even despite how disgusted he felt. "You treat Sirius like he's some piece of disgusting filth and then expect him to show you the utmost respect. You're both nothing but cruel and hateful, sorry excuses for human beings. I-"

Regulus felt himself being pulled back just as Mother lunged at him, the door slamming in her face. Sirius dragged him down the front steps into the rain, not stopping for several blocks, at which point they were both thoroughly soaked. Taking shelter under a tree, which only mildly helped, Sirius finally loosened his grip and faced Regulus.

"I need to know now how far you want to go," Sirius demanded, panting. "If you go back now, I'm sure they'll forgive you. You've always been the favorite, the one who could do no wrong. Just blame me, they always do." He said this so casually that Regulus knew it was exactly what Sirius expected him to do.

Regulus shook his head. "No. I'm done going along with whatever they want. It's not fair to treat me better just because I don't go against their wishes."

Sirius ran a hand through his wet hair, still looking as disbelieving as he had when Regulus had first stepped in to defend him. "I'm going to stay with one of my friends," Sirius finally managed. "James Potter. I'm sure his parents won't mind having you stay as well."

Regulus nodded, this plan sounding agreeable to him. As long as they got out of the rain before dark. "Lead the way."

* * *

Hours later, Regulus lay in the bed that Mr. and Mrs. Potter had kindly arranged for him in one of their guest rooms. Sirius had opted to stay with James tonight and had avoided conversation with his brother. Regulus knew he didn't trust him yet. In all the years that Sirius had been feuding with their parents, Regulus had never involved himself. He probably didn't know what to think now that Regulus had chosen to go against their parents as well.

Honestly, Regulus didn't know what to think either. He had no idea what to do now. The thought worried him, but he was confident that he'd figure something out. Besides, he had his brother, so he wasn't entirely alone.

There was a knock at the door and then a figure stepped quietly into the darkened room. "Reg? Are you awake?" Sirius whispered.

Regulus sat up. "Don't know how I could sleep," he stated. "Too much on my mind." He tucked his legs up close to his chest, making room for Sirius as he sat down at the opposite end of the bed.

"Why?" Regulus thought Sirius might have more to say, but his brother remained silent, apparently unable to say more.

Regulus didn't need to ask what his brother meant. "I don't know," he admitted. "When Father said he'd disinherit you, it was like I was seeing them for the first time as they truly were. Something in me just...changed. I feel like such a fool for following them so blindly for so long." He cringed inwardly as he remembered some of the things he'd said to Sirius while acquiescing to his parents' wishes. "I'm sorry. I know I was starting to turn into them a bit. I've said some horrid things to you. I really only said those things to make them happy. I don't think that what they say about Muggles and half-bloods is right, but I've never wanted to get on their bad side. I guess I'd just had enough finally."

"It's fine," Sirius assured him. "I...I wasn't sure what to think of your little outburst. I didn't think I could trust you. Maybe it was some elaborate trap thought up by our parents." He snickered. "But then I remembered that they aren't quite that smart."

Regulus's mouth twitched into a smile. He might've been insulted by such a comment before, but now he knew Sirius was right. Elaborate plans weren't their forte.

"I should apologize as well," Sirius said soberly. "I haven't exactly been the nicest brother to you. I've said my share of mean things to you."

Regulus shrugged. "That's all in the past. Things can be different now." But thinking about the future made Regulus start to worry all over again. "What are we going to do?" he wondered aloud. "We haven't got any money. Everything we own is still at Grimmauld Place. How will we get our things for school?"

Sirius shifted up the bed and sat next to Regulus, putting an arm around his shoulders. "Hey, I'm the oldest one. I'm supposed to be worried about how we'll survive." Sirius squeezed him reassuringly. "I'll take care of you as long as you'll let me. You trust me and I'll trust you."

Regulus nodded and leaned into his brother's one-armed embrace. They'd had their differences over the years, but he knew they were past all that now. He couldn't help but think that this was going to be good for them.

* * *

True to his word, Sirius made sure Regulus had all that he needed. The Potters supported them at first, buying all of their school things. They had loved Sirius the first time he'd come to visit James several years ago, and now they loved his little brother just as much. They were only too happy to provide a safe and loving home for the brothers.

Sirius received word shortly after he started his final year at Hogwarts that Uncle Alphard, their mother's brother, had died and left Sirius a large fortune. He split the gold with his brother, ensuring that they could both live comfortably for the rest of their lives.

When Sirius finished school and bought his own place, he insisted that Regulus live with him until he finished his own schooling. Regulus refused at first. Sirius had just married Marlene McKinnon, the girl who had been the subject of the argument that had started the brothers on this path. Regulus was reluctant to intrude in Sirius's new life.

When he voiced this opinion, Sirius just laughed and shook his head. "Intrude? Are you kidding me? I was going to ask Marlene about it when we were looking for a place, but she was the one who asked what I thought of having you live with us." Gazing at Regulus fondly, he added, "She knows how important you are to me and I know she loves you just as much as I do."

Regulus agreed, blinking back tears. He thought about how grateful he was for that last argument between Sirius and their mother, and for the split-second decision he'd made to stand up for Sirius. It had turned out to be the best thing he'd ever done.


End file.
